Compactly Stackable Scaffold Ladder Frames

ABSTRACT

A scaffold includes first and second ladder frames. Each ladder frame includes a first and second vertical supports, a center support, rung(s), and upper and lower horizontal supports. The upper horizontal support is formed of tubular material, and has a central section and flattened end sections mounted to corresponding vertical supports. The center support and/or rungs advantageously have coped and slightly flattened end sections. Recesses formed by the flattened end sections provide space to partially receive vertical or horizontal supports of another ladder frame when the frames are stacked, thereby reducing overall stack height.

This is a continuation-in-part of application Ser. No. 17/965,503, filed13 Oct. 2022, and claims benefit of U.S. Provisional Application No.63/255,126, filed 13 Oct. 2021, the disclosures both of which areincorporated herein by reference in their entirety.

TECHNICAL FIELD

The present disclosure relates generally to crimping tool for flatteningthe end of a pipe, and to a pipe with a flattened end formed by thecrimping, and to a scaffold ladder frame that employs the pipe, and torelated scaffolds and methods.

BACKGROUND

Scaffolds are commonly used in painting and other construction jobs, andtraditionally allow a deck to be mounted at a desired elevation. Atypical scaffold comprises two spaced-apart ladder frames connected bycross braces to form a self-supporting structure. Each ladder framecomprises two or more vertical posts interconnected by horizontalmembers that are welded to the vertical posts. It is known to flattenthe ends of the horizontal members to facilitate stacking of thescaffold ladder frames when not in use. When the frames are verticallystacked, the vertical post on one ladder frame rests on the flattenedends of the horizontal members on the ladder frame immediately below toenable more compact stacking. See, for example, U.S. Patent ApplicationPublication 2009/0236181.

While flattening the ends of the horizontal members facilitates stackingof the frames, the flattened ends tends to flare in both upward anddownward directions. When a walkboard (or “platform”) is laid on top ofthe horizontal member, one edge of the walkboard is lifted slightly dueto the flaring at the ends of the horizontal member. Thus, the wallboardcannot lie flat on the horizontal members.

In addition, the ladder frames typically include some intermediatehorizontal members, typically on one lateral half of the ladder frame,that act as ladder rungs. Flattening the ends of these ladder rungs tothe same extent as the main horizontal members, while facilitatingstacking, may result in relatively weaker weld joints.

As such, there remains a need for alternative approaches to formingscaffolds and/or scaffold ladder frames, preferably approaches thatadvantageously allow for better accommodation of the walkboard and/orthat provide enhanced weld strength while allowing for space consumptionfor stacking.

SUMMARY

The present disclosure is generally directed to a scaffolding andrelated products, tools, and methods that employ or help form flattenedsections that allow for smaller stacking space to be consumed whileadvantageously allowing for welded joints to retain sufficient strength.Recesses formed by the flattened end sections provide space to at leastpartially receive vertical or horizontal supports of another ladderframe when the frames are stacked, thereby reducing overall stackheight.

In one aspect, a scaffold ladder frame is disclosed. The scaffold ladderframe includes first and second vertical supports, upper and lowerhorizontal supports, a center support, and at least one rung. The upperand lower horizontal supports are formed of tubular material. The upperhorizontal support has a central section and narrowed end sections, withthe end sections mounted to corresponding vertical supports. At leastthe upper horizontal support is formed of a first size tubular material.The end sections of the first horizontal support include a generallyflat terminal section having a first width. The center support ismounted to the upper and lower horizontal supports between the verticalsupports. The center support is formed of a second size tubularmaterial, the second size smaller than the first size and larger thanthe first width. The end portion of the center support proximate theupper horizontal support is narrowed to have a second width matching thefirst width. The rung(s) rung are mounted to the first vertical supportand the center support in spaced relation to upper horizontal support.The rung is formed of second size tubular material. The end portion ofthe rung proximate the first vertical support is narrowed to have asecond width matching the first width. In some embodiments, the centralsection has a circular cross-section, and the end portion of the centersupport proximate the upper horizontal support is both coped andnarrowed.

In another aspect, a scaffold is disclosed. The scaffold comprises firstand second ladder frames, and a plurality of cross braces, with eachcross brace configured to be releasably connected to both the first andsecond ladder frames to form a self-supporting scaffold. Each ladderframe includes a pair of vertical supports, upper and lower horizontalsupports, a center support, and at least one rung. The upper and lowerhorizontal supports are formed of tubular material. The upper horizontalsupport has a central section and narrowed end sections, with the endsections mounted to corresponding vertical supports. At least the upperhorizontal support is formed of a first size tubular material. The endsections of the upper horizontal support include a generally flatterminal section having a first width. The center support is mounted tothe upper and lower horizontal supports between the vertical supports.The center support is formed of a second size tubular material, thesecond size smaller than the first size and larger than the first width.An end portion of the center support proximate the upper horizontalsupport is narrowed to have a second width matching the first width. Therung(s) are mounted to one of the first support and the center supportin spaced relation to upper horizontal support. The rung is formed ofsecond size tubular material. An end portion of the rung proximate thefirst vertical support is narrowed to have a second width matching thefirst width. In some embodiments, the end portion of the center supportproximate the upper horizontal support is both coped and narrowed.

In another aspect, a stack of scaffold ladder frames is disclosed. Thestack includes a first ladder frame and a second ladder frame stackedadjacent to the first ladder frame. Each ladder frame is laid flat andincludes first and second vertical supports; upper and lower horizontalsupports, upper and lower horizontal supports, a center support, and atleast one rung. Each upper horizontal support has a central section andnarrowed end sections, with the end sections mounted to correspondingvertical supports. The center support is mounted to the upper and lowerhorizontal supports between the vertical supports. An end portion of thecenter support proximate the upper horizontal support is narrowed. Therung is mounted to the first vertical support and the center support inspaced relation to the upper horizontal support. An end portion of therung proximate the first vertical support is narrowed. The narrowed endsection of the upper horizontal support forms a first recess; and thenarrowed end portion of the rung forms a second recess; and the narrowedend portion of the center support forms a third recess. The secondladder frame is oriented like the first ladder frame, and staggered intwo mutually orthogonal directions relative to the first ladder framesuch that: the first vertical support of the second ladder frame ispartially disposed in the first and second recesses of the first ladderframe; and the upper horizontal support of the second ladder frame ispartially disposed in the third recess of the first ladder frame. Acombined stack height of the first and second ladder frames is less thantwice a diameter of the vertical supports. In some embodiments, thehorizontal supports and the vertical supports are made from tubing thatis larger in cross-section than the rung and the center support, and thefirst recess is deeper than the second and third recesses. In someembodiments, the stack includes a third ladder frame, with the first,second, and third ladder frames being substantially identical. The thirdladder frame stacked adjacent the second ladder frame and is orientedlike the first ladder frame. The third ladder frame is staggered in twomutually orthogonal directions relative to the second ladder frame suchthat: the first vertical support of the second ladder frame is partiallydisposed in the first and second recesses of the third ladder frame; theupper horizontal support of the second ladder frame is partiallydisposed in the third recess of the third ladder frame. A combined stackheight of the first, second, and third ladder frames is less than threetimes a diameter of the vertical supports.

In another aspect, a stack of scaffold ladder frames is disclosed. Thescaffold ladder frames are as described herein. The stack includes firstand second ladder frames, with the second ladder frame stacked on top ofthe first ladder frame. In the stack, the upper horizontal support ofthe second ladder frame rests in a recess formed in the center supportof the first ladder frame at the narrowed end portion of that centersupport. The vertical support of the second ladder frame rests in arecess formed in the upper horizontal support of the first ladder frameat the narrowed end section of that horizontal support. The combinedstack height of the first and second ladder frames is less than twice adiameter of the vertical supports. In some embodiments, the first andsecond ladder frames are similarly oriented, with the second ladderframe staggered in two mutually orthogonal directions relative to thefirst ladder frame.

Related methods, components, and combinations are also disclosed.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows a front view of a ladder frame of a scaffold of FIG. 12 ,with alternative placement of latch posts.

FIG. 2 shows a top view of the ladder frame of FIG. 1 .

FIG. 3 shows a partial detail view of area A in FIG. 1 .

FIG. 4 shows a partial detail view of area C in FIG. 2 .

FIG. 5 shows a partial detail view of area Din FIG. 1 .

FIG. 6 shows a partial detail view of area E in FIG. 1 .

FIG. 7 shows a top view of a rung of the ladder frame of FIG. 1 .

FIG. 8 shows an end view of a horizontal support for the ladder frame ofFIG. 1 .

FIG. 9 shows a joint between a top horizontal support and a verticalsupport for the ladder frame of FIG. 1 .

FIG. 10A shows a view from above of a stack of a plurality of scaffoldladder frames.

FIG. 10B shows a side view of the stack of FIG. 10A, with the tops ofthe ladder frames facing the viewer.

FIG. 100 shows a partial sectional view of the stack at 10C-10C of FIG.10A, near the center support, with flattening of the ends of the centersupport exaggerated for illustrative purposes.

FIG. 11 shows a tool for forming a flattened end of a horizontalsupport, and a portion of the horizontal support so formed.

FIG. 12 is a perspective view of the scaffold with two ladder frames,with an optional walkboard omitted.

FIG. 13 and FIG. 14 show an exemplary latch post for connecting thecross brace to the vertical supports of the ladder frame.

FIG. 15 shows a simplified flow diagram of a process of making a pipewith a flattened end.

FIG. 16 shows a partial detail view of area F in FIG. 1 .

FIG. 17 shows a partial detail view of area G in FIG. 1 .

FIG. 18 shows a side view of a center support of FIG. 1 , withflattening of the ends of the center support exaggerated forillustrative purposes.

DETAILED DESCRIPTION

FIG. 12 illustrates a scaffold 10 according to an exemplary embodiment.The scaffold 10 comprises two spaced apart ladder frames 12interconnected by removable cross braces 14 to form a rectangularscaffold 10. As will be hereinafter described, the scaffold 10 isdesigned to be broken down and stored in a compact space to reduce thevolume occupied by the disassembled scaffold 10.

Each ladder frame 12 of the scaffold 10 comprises vertical supports 20,horizontal supports 30, an optional center support 25, and one or moreoptional ladder rungs 50 extending between one of the vertical supports20 and the center support 25 to form a ladder for climbing the scaffold10. See, e.g., FIG. 1 . The vertical supports 20, horizontal supports30, center support 25, and ladder rungs 50 are optionally all formedfrom metal tubular material. The cross-section of the tube isadvantageously generally elliptical, with elliptical meaning oval,circular, or other generally round shape, which does not require amathematically precise elliptical shape. In some embodiments, thegenerally elliptical cross-sections of the vertical supports 20,horizontal supports 30, center support 25, and/or ladder rungs 50 arecircular. The cross braces 14 may comprise circular metal tubing withflattened ends where the cross braces 14 connect with the frames 12. Theflattened ends may have openings formed therein that engage withinwardly projecting latch posts 100 on the vertical supports 20 of theladder frames 12. Note that the latch posts 100 in FIG. 12 are shown inan alternative location compared with the latch posts 100 of FIG. 1 ;any suitable location may be used for the latch posts 100 based ondesired stability, ease of manufacturing, or other considerations.

The vertical supports 20 each extend along a respective longitudinalaxis 21 that is vertically oriented. The vertical supports 20 have latchposts 100 mounted thereto at appropriate locations, for mating with thecross braces 14 as discussed above. The vertical supports 20 optionallyalso include additional features, such as for receiving optional wheels,which are omitted from discussion herein in the interest of clarity.

The horizontal supports 30 each extend along a respective longitudinalaxis 31 that is horizontally oriented. The horizontal supports 30include a base or central section disposed between the end sections 40.As mentioned above, the horizontal supports are formed from metaltubing, which may have an elliptical cross-section. The central section35 of the horizontal supports 30 has an upper or top centerline 36 onthe upper surface parallel with the longitudinal axis 31, and a lower orbottom centerline 37 on the lower surface parallel with the longitudinalaxis 31. Note that the longitudinal axis 31 is at the geometric centerof the cross-section. Typically, there are two horizontal supports oneupper and one lower, but there may be other numbers of horizontalsupports 30.

The respective end portions 40 of the horizontal supports 30 haveflattened sections 42. The flattened sections 42 have a reduceddimension (width W) when viewed from above relative to the centralsection, see FIG. 2 and FIG. 4 . Each flattened section 42 includes arelatively flat terminal section 44, and a transition section 46. Theflat terminal section 44 has an elongated (e.g., oval) cross-section,and is the portion of the horizontal support 30 mounted to the verticalsupport 20. The terminal section 44 is advantageously formed by crimpingthe end of the tube forming the vertical support 20. The crimping isadvantageously such that there remains a gap between the “sides” of thecrimped section. That is, the terminal section 44 advantageously remainshollow. This shape aids in forming a good weld joint when the terminalsection 44 is welded to the vertical support 20. It is intended that theterminal section 44 have a longitudinal length that is sufficient toproperly receive a vertical support 20 of another ladder frame 12 whenthe ladder frames 12 are stacked. See FIG. 10B. The transition sectionis disposed 46 between the terminal section 44 and the central section35, and has a width that gradually narrows from the width of the centralsection 35 to the width W of the terminal section 44. The narrowing ofthe terminal section 44 forms a pair of recesses 48 that have a depth 48d. It should be noted that the terminal section 44 is disposedasymmetrically about the longitudinal axis of the horizontal support 30.In particular, the top T of the terminal section 44 aligns with the topcenterline 36 of the central section 35, but the bottom B of theterminal section 44 is disposed so that the bottom B of the terminalsection 44 extends below the bottom centerline 37 of the central section35. Thus, the flattened terminal section 44 extends downward from thecentral section 35, but does not extend upward from the terminal section44. As such, the upper surface of the horizontal support 30 is at aconsistent elevation, allowing a walkboard 16 placed thereon to restfirmly on the horizontal support 30 without being lifted off thehorizontal support 30 near the joint of the horizontal support 30 to thevertical support 20. See FIG. 9 . Accordingly, the corners of thewalkboard 16 can “rest flat” on the horizontal support 30.

The optional center support 25 is disposed generally parallel to thevertical supports 20 in spaced relation to the vertical supports 20. Thecenter support is advantageously mounted at its upper and lower ends tothe horizontal supports 30.

As mentioned above, the ladder frame 12 advantageously includes one ormore ladder rungs 50 that are mounted to center support 25 and one ofthe vertical supports 20, so as to be generally parallel to horizontalsupport 30 and spaced therefrom. The tubing of the ladder rung 50extends along a corresponding longitudinal axis 51. In order tofacilitate solid connections to the center support 25 and the verticalsupport 20, the ladder rung 50 is advantageously tube coped on each end52 to mate up with the corresponding vertical element. The ladder rung50 is welded on one end 52 to the center support 25 and on the other endto the vertical support 20. In some embodiments, the ladder rungs 50 aremade of the same size tubing as the horizontal supports 30, andoptionally include asymmetrically flattened terminal sections on theirends to aid in stacking ladder frames 12 in offset arrangement as shownin FIGS. 10A-C. However, the ladder rungs 50 may optionally be made fromtubing that is smaller than the tubing forming the horizontal supports30 and vertical supports 20. When the ladder rung 50 is made fromsmaller tubing, some space is provided for stacking another ladder frame12 in offset arrangement as shown in FIG. 100 . However, if the size ofthe tubing for the ladder rung 50 is larger than the thickness of theterminal section 44 of the horizontal support 30, the ladder rung 50 maycause the stacked ladder frames 12 to be vertically offset more thannecessary when stacked because the vertical support 20 of the otherladder frame 12 may rest on the ladder rung 50 rather than on theterminal section 44. As such, some embodiments of the ladder frame 12employ ladder rungs 50 that have one or both of their coped ends 52slightly flattened. That is, the ends 52 are both coped and slightlyflattened, in either order but advantageously coped and then slightlyflattened. For example, if the thickness of the terminal section 44 is22.2 mm, and the ladder rung 50 is formed of 25.4 mm diameter tubing,the coped end portions of the ladder rung 50 may be slightly flattened(e.g., by crimping) so that the slightly flattened end portion 52mounted to the vertical support 20 (and optionally both ends 52 tofacilitate manufacture) has a front-to-back width (into the pagethickness for the FIG. 1 view) of 22.2 mm or less. The narrowing of theends 52 forms a pair of recesses 58 that have a depth 58 d. Note thatdepth 58 d can advantageously be less than depth 48 d when the ladderrungs 50 are made from tubing that is smaller than the tubing formingthe horizontal supports 30 and vertical supports 20. With suchembodiment(s), the vertical support 20 of the other (“top”) ladder frame12 may rest on both the ladder rung and the terminal section(s) 44 ofthe (“bottom”) ladder frame 12 when stacked. Thus, the vertical support20 is at least partially disposed in recess 58. This allows for minimalheight to be consumed by the stacked ladder frames 12.

In some embodiments, the ladder frame 12 does not include an centersupport and the ladder rungs 50 are mounted to a vertical support 20 oneach end. Thus, the ladder rungs 50 are approximately as long as thehorizontal supports 30 and reach from the vertical support 20 on onelateral side of the ladder frame 12 (for the orientation shown in FIG. 1) to the vertical support 20 on the other lateral side of the ladderframe 20.

In an exemplary embodiment, the vertical supports 20 and horizontalsupports 30 can be formed of 41.3 mm diameter steel pipe. The verticalsupports 20 may be about 1524 mm long and spaced about 1524 mm apart.The center support 25 may be formed of 25.4 mm diameter steel pipe, with41.3 mm coping on each end. The ladder rungs 50 may be formed of 25.4 mmdiameter steel pipe, with 25.4 mm coping on one end and 41.3 mm copingon the other end. The end 52 of rung 50 with 41.3 mm coping, or bothends 52, may be slightly flattened to a thickness of about 22.2 mm. Theupper horizontal support 30 may be placed so that the upper surface ofthe horizontal support 30 is about 9.8 mm down from the upper end of thevertical supports 20, and the lower horizontal support 30 may be locatedabout 1143 mm from the upper horizontal support 30. The width (front toback thickness for the orientation of FIG. 1 ) of the terminal section44 may be about 22.2 mm, and the terminal section 44 may be about 50 to55 mm long in a direction parallel to longitudinal axis 31. The terminalsection 44 may have a height (distance between top T and bottom B) ofapproximately 52 mm. Thus, by way of example, the ratio of height towidth for the terminal section 44 may be approximately 2.5:1. In otherembodiments, the width of the terminal section 44 may be about 16 mm,and the terminal section 44 may be about 50 to 55 mm long in a directionparallel to longitudinal axis 31. The terminal section 44 may have aheight (distance between top T and bottom B) of approximately 56 mm.Thus, by way of example, the ratio of height to width for the terminalsection 44 may be approximately 3.5:1. In other embodiments, the ratioof the height to width of the terminal section 44 may be betweenapproximately 3.5:1 and approximately 1.8:1.

FIGS. 13-14 show an exemplary latch post 100. The latch post 100includes a slot 102 to receive a locking member 104. The locking member104 is secured in the slot 102 by a pivot pin 106 disposed at the outerend of the latch post 100. A second pin 108 is received in a slot 110 inthe locking member 104. This arrangement allows the locking member 104to drop down under the force of gravity and thus serve as a latch as toretain the cross brace 14 on the latch post 100. During assembly of thescaffold 10, the cross braces 14 engage with the latch posts 100 on theladder frames 12 of the scaffold. The cross braces 14 optionally haveflattened ends with openings formed therein. The openings in the ends ofthe cross braces 14 will pass over the latch posts 100 and push thelocking member 104 upwardly. Once the opening in the cross brace 14passes over the locking member 104, the locking member 104 will dropdown under the force of gravity to latch the cross brace 14 and preventit from disengaging. In some embodiments, the cross braces 14 may beunitary, and optionally pivotably connected together. However, in orderto facilitate compact storage, the cross braces 14 may advantageously betelescoping and/or composed of multiple segments releasably connected inseries.

The end section(s) 40,52 of the horizontal support(s) 30 and/or therungs 50 may be formed by crimping the end section(s) 40,52 with asuitable die tool. An example of a suitable tool for forming the endsection 40 of the horizontal support 30 is shown in FIG. 11 . The toolincludes a first die half 82 and a second die half 84 that jointly forma die 80. Each of the die halves 82,84 have cavities 86 therein whichare designed to receive the end of a tubular pipe section 90 from whichthe horizontal support 30 is formed. Conceptually, the tubular pipesection 90 has a base section 92 which remains undeformed in thecrimping process, and an end portion 94. The cavities 86 of the firstand second die halves 82,84 have a first section 87 and a second section88. The first section 87 is shaped to conform to the base section 92 ofthe tubular pipe section 90. The second section 88 is shaped toasymmetrically flatten the end portion 94 to have an elongatedcross-section relative to the base section 92. The deformation is suchthat the material of the tubular pipe section 90 is preferentiallydisplaced, laterally in FIG. 11 , in one direction over an opposingdirection. The resulting elongated cross-section is such that a top T ofthe flattened end aligns with a top centerline 36 of the base section 92and a bottom B of the flattened end extends below a bottom centerline 37of the base section 92. If desired, the die 80 can be mounted to a dieshoe on spacer blocks, and can be mounted by bolting, welding, or anyother means known in the art. The use of the die 80 allows the crimpingprocess to flatten the tubular material inserted therein in a consistentmanner.

Referring to FIG. 15 , a process (200) for forming a pipe 90 with anasymmetric flattened end portion 94 includes inserting (210) a tubularpipe section 90 into a crimping die 80, with tubular pipe section 90having an undeformed base section 92 and an end portion 94. The processalso includes compressing (220) the end portion 94 to form anasymmetrically flattened end with an elongated cross-section compared tothe base section 92 such that a top T of the flattened ends aligns witha top centerline 36 of the base section 92 and a bottom B of theflattened end extends below a bottom centerline 37 of the base section92.

The formed horizontal support 30 is an example of a pipe for use inscaffolding. Such a pipe 90 includes a tubular section with centralsection 35 and an asymmetric flattened end having an elongatedcross-section. A top T of the end section aligns with a top centerline36 of the central section 35. and a bottom B of the end section extendsbelow a bottom centerline 37 of the central section 35.

The presence of the flattened terminal sections 44 on the horizontalsupport 30 allows a plurality of ladder frames 12 to be stacked in aslightly staggered arrangement (see FIGS. 10A-C) while consuming lessvertical space. This is because the vertical support 20 of one ladderframe 12 rests partially in a recessed area 48 formed by the terminalsection 44 of the ladder frame 12 below it, and partially in a recessedarea 48 formed by the terminal section 44 of the ladder frame 12 aboveit. Thus, a stack 18 of N ladder frames 12 has a height that is lessthan N times the “height” of the vertical supports 20 (measured normalto the longitudinal axis 21, e.g., diameter). In addition, having theflattened terminal sections 44 asymmetrically disposed relative to thelongitudinal axis 31 of the horizontal support 30 allows the “hump”formed by the deformed material forming the terminal section 44 to belocated on one side, e.g., the lower side, of the horizontal support 30,thereby avoiding having the walkboard 16 rest on the humps. Separately,or in addition, the optional slight flattening of one or both lateralends 52 of the rungs 50 advantageously helps prevent the rungs 50 fromadding to the height of the stack 18 of ladder frames 12 (by effectivelyreducing their “height” in the area where the vertical support 20 ofanother ladder frame 12 will be resting), and/or provides a goodconfiguration for welding.

In some embodiments, the center support 25 may optionally also havecoped end portions 27 that are slightly crimped, similar to the lateralends 52 of ladder rungs 50 discussed above. The tubing of the centersupport 25 extends along a corresponding longitudinal axis 26. In orderto facilitate solid connections to the horizontal supports 30, thecenter support 25 may be advantageously tube coped on each end 27 tomate up with the corresponding horizontal support 30. The center support25 is welded on one end 27 to the upper horizontal support 30 and on theother end 27 to the lower horizontal support 30. The center support 25may optionally be made from tubing that is smaller than the tubingforming the horizontal supports 30 and vertical supports 20, which mayoptionally be of the same size as the rungs 50. When the center support25 is made from smaller tubing, some space is provided for stackinganother ladder frame 12 in offset arrangement as shown in FIGS. 10A-C.However, if the size of the tubing for the center support 25 is, alongits entire length, larger than the width W of the terminal section 44 ofthe horizontal support 30, the center support 25 may cause the stackedladder frames 12 to be vertically offset more than necessary whenstacked because the horizontal support 30 of the other ladder frame 12may rest on the center support 25. As such, some embodiments of theladder frame 12 employ center support 25 that have one or both of theircoped ends 27 slightly flattened. See FIGS. 100 and 18 , where theslight flattening of the end 27 is exaggerated to illustrative purposes.The ends 27 are both coped and slightly flattened, in either order butadvantageously coped and then slightly flattened. For example, if thethickness of the terminal section 44 is 22.2 mm, and the center support25 is formed of 25.4 mm diameter tubing, the coped end portions 27 ofthe center support 25 may be slightly flattened (e.g., by crimping) sothat the slightly flattened end portion 27 mounted to the horizontalsupport 30 (and optionally both ends 52 to facilitate manufacture) has afront-to-back width (into the page thickness for the FIG. 1 view) of22.2 mm or less. Note that the slight flattening may be symmetricrelative to axis 26, or may be asymmetric, and may use a process similarto that discussed above with respect to the ladder rungs 50. Thenarrowing of the ends 27 forms a pair of recesses 28 that have a depth28 d. Note that depth 28 d can advantageously be less than depth 48 dwhen the center support 25 is made from tubing that is smaller than thetubing forming the horizontal supports 30 and vertical supports 20, andmay optionally be approximately equal to depth 58 d. With suchembodiment(s), the horizontal support 30 of the other (“top”) ladderframe 12 may rest on both the center support 25 and the verticalsupports 20 of the (“bottom”) ladder frame 12 when stacked. Thus, thehorizontal support 30 is at least partially disposed in recess 28. Thisallows for minimal height to be consumed by the stacked ladder frames12.

A stack 18 of ladder frames 12 is shown in FIGS. 10A-C. The ladderframes 12 in the stack 18 are one or more embodiments as describedherein. Advantageously, the ladder frames 12 are substantiallyidentical. As shown, the ladder frames 12 may be stacked with the ladderframes 12 in the same orientation. Thus, for example, the upperhorizontal supports 30 of adjacent ladder frames 12 are closer to eachother than they are to their respective lower horizontal supports 30.Within the stack 18, an upper frame 12 rests on adjacent lower frame 12,and is staggered in two mutually orthogonal directions relative to thelower frame 12 (e.g., south and west in FIG. 10A, or south and east, ornorth and west, etc.). The upper frame's upper horizontal support 30disposed partially in recess 28 (associated with center support 25) oflower frame 12, and the upper frame's vertical support 20 disposedpartially in the recess 48 (associated with upper horizontal support 30)of lower frame 12 and also partially in the recess 58 (associated withrung 50) of lower frame 12. And, if there is also a “top” frame 12stacked above the upper frame 12, then the upper frame's upperhorizontal support 30 is also disposed partially in recess 28(associated with center support 25) of top frame 12, and the upperframe's vertical support 20 is also disposed partially in the recess 48(associated with upper horizontal support 30) of top frame 12 and alsopartially in the recess 58 (associated with rung 50) of top frame 12.This compact stacking of the ladder frames 12 allows the stack height Hto be smaller than is conventional, thereby reducing transportcosts/difficulty. The stack height H of stacked ladder frames 12 is theheight of the stack 18 of ladder frames 12 when the ladder frames 12 arelaid flat, as measured into the page for the orientation of FIG. 1 . SeeFIG. 10B. Note that the roles of the upper frame 12 and lower frame 12may be reversed, and an “upper” frame 12 may act as a “lower” frame 12with respect to a different adjacent frame 12, such as a third “top”frame 12 in the stack 18.

Note that the compact stacking of the present disclosure can be achievedwith either asymmetric or symmetrically formed flattened sections 42.Also, the ability of the walkboard 16 to lay flat on the upperhorizontal support 30 due to the absence of “hump” due to asymmetricflattening of the flattened end sections 42 can be achieved with orwithout the rungs 50 and/or center support 25 having slightly flattenedends.

As used herein, a claim requirement of “a X” means having one more X's,and a claim requirement of “a pair of X” means having two or more X's.The terms “upper” and “lower”, and “horizontal” and “vertical” are usedwith reference to the orientation of the ladder frame 12 as shown inFIG. 1 for purposes of clarity. A frame 12 falling within the scope of aclaim here if in the orientation of FIG. 1 is also intended to bewithing the scope of the claim if in any other orientation, such asinverted or rotated ninety degrees.

The present disclosure may, of course, be carried out in other specificways than those herein set forth without departing from the scope andessential characteristics of the disclosure. The present embodimentsare, therefore, to be considered in all respects as illustrative and notrestrictive, and all changes coming within the meaning and equivalencyrange of the appended claims are intended to be embraced therein.

What is claimed is:
 1. A stack of scaffold ladder frames, comprising: afirst ladder frame and a second ladder frame stacked adjacent to thefirst ladder frame; wherein each ladder frame comprises: first andsecond vertical supports; upper and lower horizontal supports; the upperhorizontal support having a central section and narrowed end sections,with the end sections mounted to corresponding vertical supports; acenter support mounted to the upper and lower horizontal supportsbetween the vertical supports; wherein an end portion of the centersupport proximate the upper horizontal support is narrowed; at least onerung mounted to the first vertical support and the center support inspaced relation to upper horizontal support; wherein an end portion ofthe rung proximate the first vertical support is narrowed; wherein thenarrowed end section of the upper horizontal support forms a firstrecess; wherein the narrowed end portion of the rung forms a secondrecess; wherein the narrowed end portion of the center support forms athird recess; wherein the second ladder frame is oriented like the firstladder frame, and wherein the second ladder frame is staggered in twomutually orthogonal directions relative to the first ladder frame suchthat: the first vertical support of the second ladder frame is partiallydisposed in the first and second recesses of the first ladder frame; theupper horizontal support of the second ladder frame is partiallydisposed in the third recess of the first ladder frame; a combined stackheight of the first and second ladder frames is less than twice adiameter of the vertical supports.
 2. The stack of claim 1: wherein thehorizontal supports and the vertical supports are made from tubing thatis larger in cross-section than the rung and the center support; andwherein the first recess is deeper than the second and third recesses.3. The stack of claim 1: further comprising a third ladder frame;wherein the first, second, and third ladder frames are substantiallyidentical; the third ladder frame stacked adjacent the second ladderframe; wherein the third ladder frame is oriented like the first ladderframe, and wherein the third ladder frame is staggered in two mutuallyorthogonal directions relative to the second ladder frame such that: thefirst vertical support of the second ladder frame is partially disposedin the first and second recesses of the third ladder frame; the upperhorizontal support of the second ladder frame is partially disposed inthe third recess of the third ladder frame; a combined stack height ofthe first, second, and third ladder frames is less than three times adiameter of the vertical supports.
 4. The stack of claim 1, wherein, foreach ladder frame: the central section has a circular cross-section; andthe end portion of the center support proximate the upper horizontalsupport is both coped and narrowed.
 5. The stack of claim 4, wherein,for each ladder frame, the end portion of the rung is both coped andnarrowed.
 6. A scaffold ladder frame, comprising: first and secondvertical supports; upper and lower horizontal supports formed of tubularmaterial; the upper horizontal support having a central section andnarrowed end sections, with the end sections mounted to correspondingvertical supports; wherein the upper horizontal support is formed of afirst size tubular material; wherein the end sections of the upperhorizontal support include a generally flat terminal section having afirst width; a center support mounted to the upper and lower horizontalsupports between the vertical supports; wherein the center support isformed of a second size tubular material, the second size smaller thanthe first size; wherein the second size is larger than the first width;wherein an end portion of the center support proximate the upperhorizontal support is narrowed to have a second width matching the firstwidth; at least one rung mounted to the first vertical support and thecenter support in spaced relation to upper horizontal support; whereinthe rung is formed of second size tubular material; wherein an endportion of the rung proximate the first vertical support is narrowed tohave a second width matching the first width.
 7. The scaffold ladderframe of claim 6, wherein the central section has a circularcross-section, and wherein the end portion of the center supportproximate the upper horizontal support is both coped and narrowed. 8.The scaffold ladder frame of claim 6, wherein the first width isapproximately half a diameter of the one of the vertical supports. 9.The ladder frame of claim 6, wherein each end of the center support isnarrowed and coped.
 10. The scaffold ladder frame of claim 6: whereinthe end sections of upper horizontal support are asymmetrically narrowedand have vertically elongated cross-sections compared to the centralsection; wherein the central section of the upper horizontal support hasa top centerline and a bottom centerline; wherein a top of the endsection of the upper horizontal support aligns with the top centerlineof the central section; and wherein a bottom of the end section of theupper horizontal support is disposed below the bottom centerline of thecentral section.
 11. A scaffold, comprising: first and second ladderframes, each ladder frame comprising: first and second verticalsupports; upper and lower horizontal supports formed of tubularmaterial; the upper horizontal support having a central section andnarrowed end sections, with the end sections mounted to correspondingvertical supports; wherein the upper horizontal support is formed of afirst size tubular material; wherein the end sections of the upperhorizontal support include a generally flat terminal section having afirst width; a center support mounted to the upper and lower horizontalsupports between the vertical supports; wherein the center support isformed of a second size tubular material, the second size smaller thanthe first size; wherein the second size is larger than the first width;wherein an end portion of the center support proximate the upperhorizontal support is narrowed to have a second width matching the firstwidth; at least one rung mounted to the first vertical support and thecenter support in spaced relation to upper horizontal support; whereinthe rung is formed of second size tubular material; wherein an endportion of the rung proximate the first vertical support is narrowed tohave a second width matching the first width; a plurality of crossbraces, each configured to be releasably connected to both the first andsecond ladder frames to form a self-supporting scaffold;
 12. Thescaffold of claim 11, wherein the end portion of the center supportproximate the upper horizontal support is both coped and narrowed. 13.The scaffold of claim 11, wherein both ends of the center support arenarrowed and coped.
 14. The scaffold of claim 11, wherein the secondsize is about 60% of the first size.
 15. The scaffold of claim 11,wherein there are at least two rungs for each ladder frame.
 16. Thescaffold of claim 11, further comprising a walkboard configured to besupported by the upper horizontal supports of the first and secondladder frames.
 17. The scaffold of claim 11, wherein the secondhorizontal supports also have narrowed end sections.
 18. The scaffold ofclaim 17, wherein the end sections of the second horizontal supports areasymmetrically flattened end sections.
 19. The scaffold of claim 11,wherein, for each ladder frame: the central section of the tophorizontal support has a top centerline and a bottom centerline; thenarrowed end sections of the upper horizontal support are asymmetricallyflattened end sections having a vertically elongated cross-sectioncompared to the central section; a top of each end section aligns withthe top centerline of the central section; and a bottom of each endsection is disposed below the bottom centerline of the central section.20. The scaffold of claim 11, wherein, for each ladder frame, thecentral section of the upper horizontal support has a circularcross-section.